| Phthalate esters(PAEs),as the most commonly used plasticizer,is usually adopted in plastic products and is widely used in the plastic packaging industry of food and medicine.When the food is in contact with the packing materials and containers containing PAEs,the PAEs unit may migrates and dissolve in the food,causing food pollution and directly endangers human health.However,such substances are a kind of environmental estrogens in biological characteristics,and their toxicity has attracted increasing concern.In order to ensure environmental safety and human health,all countries in the world have taken different measures to limit the content of PAEs in food packaging,medical products and toys,and the detection of PAEs in food tends to be strict.In view of the relative backwardness of domestic analysis methods and the limitation of the lack of reference materials,this thesis has improved the existing detection methods and determined a rapid and convenient preprocessing condition,and established a method for the determination of PAEs in edible oil by isotope dilution gas chromatography-mass spectrometry(GC-MS),which has strong controllability,low detection limit and high accuracy,being applied to the preparation and testing for reference materials.The two purification methods of gel permeation chromatography and solid phase extraction were compared,and the sample was purified and concentrated by the automatic gel permeation chromatography separation equipment.The optimization of the parameters,such as the selection of the filler,the ratio of the mobile phase,the optimization of the collection time of the target compounds,the sample quantity and so on,was used to determine the optimum conditions for the purification of the gel chromatography.The mobile phase is cyclohexane:ethyl acetate(1:1),the flow rate is 3.5mL/min,and the collection time of the eluent of GPC optimization is 8-16 mins.Through the selection of chromatographic column,optimization of the inlet temperature and the optimization of mass spectrum conditions,the optimum analysis conditions were determined,so that the 8 kinds of PAEs could be separated well.The internal standard method is used for qualitative and quantitative analysis of 8 kinds of PAEs in the SIM mode.There is a good linear relationship between 8 kinds of PAEs in the concentration range of 2-10?g ·g-1(the correlation coefficient R2 is greater than 0.998),and the detection limit of the method is 0.10-0.46 ?g·kg-1.The limit of quantification(10 S/N)is 0.35-1.35 }ig kg-1.Through this method,the recovery rate of 8 kinds of PAEs in edible oil ranges between 89.54-101.89%,and the relative standard deviation in repeated experiment ranges between 2.1-7.7%,thus the actual analysis needs were met.On the basis of the analysis method,8 samples of commercial edible oil were sampled randomly,and the content of 8 kinds of PAEs was measured to verify whether the method met the actual analysis needs.The purity testing of 8 pure PAEs products in reference materials were determined by gas phase hydrogen flame detector.The reference materials for plasticizer in 239 units of edible oil were prepared,and 8 kinds of PAEs in edible oil were determined.The liquid chromatography mass spectrometry(HPLC-MS/MS)was used to verify the numerical results anhe two method numerical results RSD ranges between 0.71-3.56%.The homogeneity and stability of 8 kinds of PAEs reference materials in edible oil were determined,and the uncertainty of fixed value results is also discussed.The target object of this thesis is PAEs,which is seriously harmful to human health.The research and application of its analytical method boasts important reference significance. |
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